With the fast development of computer technology and network technology, the amount of information provided by electronic devices such as mobile phones, computers and so on through the Internet is increasing explosively. Electronic information is stepping into people's life progressively, and is gradually replacing conventional books, newspapers, magazines and so on.
Electronic text is a very common carrier for electronic information. For example, electronic books present the content of books in the form of electronic text to users; network news is also mainly provided to users in the form of electronic text; email, instant messenger software or the like also mainly present information through electronic text; and so on. Users may read electronic text to obtain corresponding information.